Perfume delivery and longevity on fabrics from fabric softening compositions are especially important functions of these fabric softening compositions to provide an olfactory aesthetic benefit and to serve as a signal that fabrics are clean. Continuous efforts are made for improvements. Generally these improvements center around the proper selection of carrier materials to improve deposition of the perfume onto the fabric, controlling the rate of release of the perfume, and the proper selection of the perfume components. For example, carriers, such as microcapsules and cyclodextrin, are disclosed for example in U.S. Pat. No. 5,112,688, issued May 12, 1992 to D. W. Michael and U.S. Pat. No. 5,234,611, issued Aug. 10, 1993 to Trinh, Bacon, and Benvegnu, said patents being incorporated herein by reference. While these improvements are useful, they do not solve all problems associated with perfume delivery and longevity from fabric softening compositions.
In the rinse cycle of the laundry process, a substantial amount of perfume in the fabric softener composition can be lost when the rinse water is spun out (in a washing machine), or wrung out (during hand washing), even if the perfume is encapsulated or included in a carrier.
Furthermore, due to the high energy input and large air flow in the drying process used in the typical automatic laundry dryers, a large part of most perfumes provided by fabric softener products is lost from the dryer vent. Perfume can be lost even when the fabrics are line dried. Concurrent with effort to reduce the environmental impact of fabric softener compositions, by the development of rapidly biodegradable softener ingredients, see, for instance, copending U.S. patent application Ser. No. 08/142,739, filed Oct. 25, 1993, Wahl, et al., and U.S. patent application Ser. No. 08/101,130, filed Aug. 2, 1993, Baker, et al.; it is desirable to formulate efficient, enduring fabric softener perfume compositions that remain on fabric for aesthetic benefit, and are not lost, or wasted, without benefiting the laundered clothes.
The present invention provides improved compositions with less environmental impact due to using a combination of biodegradable softener and efficient perfumes in rinse-added fabric softening compositions while, surprisingly, also providing improved longevity of perfumes on the laundered clothes, by utilizing enduring perfume compositions. Furthermore, surprisingly, the efficient perfumes also improve the viscosity stability of the softener compositions as compared to similar compositions containing more traditional perfumes.